Retro Campag axle problem

:''(
A broken rear axle in my 1989 Athena hub has led to my LBS struggling to find a replacement (130 spacing) They found a 10x26 axle which should fit but the cones are very tight, have heard that Campag made axles with another tread pitch around this time.

Can anyone clarify, what was the threading and where might I get one? Not much to ask